Tunnel boring machines are known which include a large movable structure consisting of a large movable workshop in front of which is disposed a shield having a cross-section compatible with the future cross-section complying with the final shape of the tunnel (tunnel with a circular, two-lobe, rectangular section . . . )
The anterior portion of the shield which comes into contact with the working face to perform the cutting of the geological formation through which the tunnel passes includes a cutting head supporting working tools and driven in rotation at a predetermined speed which depends on the nature of the ground to be excavated.
Behind the shield, the tunnel boring machine includes a backup train, also known under the designation of back-up, which moves forward at the same time as the cutting head during the boring of the tunnel.
This backup train moves on a circulation route resting on the concrete shell of the tunnel and is composed of several trailers (or wagons) containing different operating modules, such as for example power supply units, hydraulic systems, ventilating air supply devices or even sanitary facilities.
In order to allow the transit of equipment necessary for the operation between the outside and the backup train, a passage is provided in the lower portion of the trailers so as to allow the circulation of a Multiservice Vehicle MSV for conveying arch segments and other consumables (spare parts, pipes, equipment baskets, etc.) from the rear of the backup train to the shield.
It is therefore necessary to provide, within each trailer, a passage of sufficient size to allow the introduction and the circulation of an MSV, which penalizes the general bulk of each trailer, these also having to transport the operating modules. Moreover, current regulations require the presence of maximally rectilinear corridors allowing evacuation, if necessary, of operators working on site, and more particularly from the shield of the tunnel boring machine. It is also necessary to provide additional corridors for the maintenance of equipment and the transport of parts. These corridors and this passage consequently intrude on the space available for the operating modules.
Finally, the circulation of the MSV within the trailers causes safety problems, the operators having a tendency, or being constrained, depending on the models and sizes of tunnel boring machines, to pass by the same circulation route as the VMS. Such joint activity, however, is not acceptable from the safety standpoint.
Document JP H11 30096 describes a trailer of a backup train of a tunnel boring machine conforming to the preamble of claim 1. More precisely, the trailer comprises a cart mounted on rollers and configured to transport arch segments by moving on a chassis situated in the lower portion of the trailer. To this end, the cart is guided along the trailer using rails, extending on either side of the cart, and moved by the wheels.